The present invention relates, in general, to a highly versatile, automated system for processing blood, blood components, and other fluids included in such processing. More particularly, the present invention relates to an automated system that can separate blood into two or more blood components (xe2x80x9capheresisxe2x80x9d), and then perform a further procedure involving one or more of the separated components.
The term xe2x80x9capheresisxe2x80x9d means removing whole blood from a patient or donor and separating the blood into two or more components. A separated component can be collected from a healthy donor, and later transfused to a patient in need of the component. Apheresis is also used in therapeutic applications to treat illness by removing diseased or otherwise undesirable components from a patient.
In a basic apheresis procedure, blood is withdrawn from a donor through a needle inserted into the vein of a donor. The needle is attached to one end of a plastic tube which provides a flow path for the blood. The other end of the tube terminates in a container for collecting the blood. The collected blood is then separated in a separator, such as a centrifuge, into its components. The desired blood component which, depending on the procedure, can be red blood cells, platelets, plasma, white blood cells or stem cells may be collected and stored for later transfusion to a patient in need of the blood component.
More recently, xe2x80x9cautomatedxe2x80x9d apheresis systems have come into widespread use. These automated systems utilize disposable, pre-sterilized fluid circuits (i.e., tubing sets) through which the blood flows. The fluid circuits are mounted on re-usable hardware devices or modules that have pumps, valves, sensors and the like. These automated systems further include an internal computer and associated software programs (controller) which control many of the processing functions.
For example, in an automated system, blood flow through the fluid circuit, the operation of valves and pumps, may be monitored and regulated by the system. An automated system can be programmed to initiate, terminate or otherwise control certain functions based on patient or donor data (e.g., height, weight, sex, hematocrit). Likewise, an automated system may monitor certain functions with the aid of sensors which can, for example, sense the amount of the collected or withdrawn component. Optical sensors are used to measure the clarity or content of a fluid, or sense the presence or absence of certain components.
Automated apheresis systems are available from several different manufacturers. Examples of commercially available apheresis systems include the AUTOPHERESIS C(copyright) Cell Separator and the ANICUS(copyright) Cell Separator, sold by Baxter Healthcare Corporation of Deerfield, Ill. The AUTOPHERESIS C(copyright) utilizes a separator that includes a chamber and rotating membrane. Blood is introduced into the chamber and the membrane separates the blood into (at least) plasma and red blood cells, or other plasma-depleted blood.
The AMICUS(copyright) Cell Separator utilizes a centrifugal separation principle. In the AMICUS(copyright) Separator, whole blood is introduced into a dual-chambered or single-chambered container mounted on a rotatable centrifuge. Whole blood is introduced into the first chamber where red blood cells are separated from platelet-rich plasma (PRP). The PRP flows into a second chamber where it is further separated into platelets and platelet-poor plasma. The disposable fluid circuit of AMICUS(copyright) uses preformed cassettes with flow paths defined therein, which is mounted on the AMICUS(copyright) device. Flow through the flow path is assisted by peristaltic pumps. A more detailed description of the AMICUS(copyright)Separator is provided in U.S. Pat. No. 5,868,696, which is incorporated herein by reference.
Recently, a more, portable automated apheresis system has been developed by Baxter Healthcare Corporation. As described in U.S. Pat. No. 6,325,775 entitled xe2x80x9cSelf-Contained Transportable Blood Processing Device,xe2x80x9d which is incorporated herein by reference, the portable apheresis system is also based on the principle of centrifugal separation. It includes a re-usable hardware module and a disposable fluid circuit. The fluid circuit includes a cassette with pre-formed flow paths, valving stations and pumping stations.
Other manufacturers such as Gambro BCT, Haemonetics, Dideco and Fresenius also provide automated apheresis systems based on centrifugal or other separation principles.
While efforts continue to develop and provide more efficient, economical and easy-to-use apheresis systems, concerns about the availability and safety of the blood supply, as well as an increased understanding of the role of certain blood components and blood related diseases, have led to the development of additional blood related procedures. These additional procedures often include treatment of the blood component so as to provide a safer or more viable component. Some of the additional procedures may involve eradication or removal of undesired compounds or other substances from blood. Some of these additional procedures may involve replacement of component with another solution. In any case, these procedures often involve many manual steps, several different pieces of equipment or complex fluid circuits. Thus, there exists a need for an automated system that, in addition to separating blood into its components, can carry out one or more other procedures involving the separated components and/or the treatment thereof.
Thus, it would be desirable to provide an automated system that can perform additional procedures using a single piece of re-usable hardware and an easy-to-load, easy-to-use disposable that eliminates the need for many tubing connections and complex routing of tubing. It would also be desirable to provide a single system that does not require regular operator intervention to perform the selected separation and other treatment or processing steps. It would also be desirable to provide a system where all desired separation and processing steps are performed within a single integrated system, and xe2x80x9coff-linexe2x80x9d treatment using separate devices is not required. It would also be desirable to provide a system that can perform multiple fluid separation, processing and/or treatment steps through automated control of flow through the fluid circuit.
One application where automated separating and processing of blood may be desirable is in the automated pre-surgical donation of blood and administration of a replacement fluid such as a blood substitute and/or oxygen carrier. A manual version of this process is described in U.S. Pat. No. 5,865,784, incorporated herein by reference.
Another application where automated separating and processing blood may be desirable is in the salvaging of red blood cells during surgery on a patient. In cell salvage, blood from a wound area or from the body cavity (i.e., extra-vascular or xe2x80x9cshedxe2x80x9d blood) that would otherwise be lost, is collected, processed (or cleaned), and the cleaned blood is returned to the donor. Examples of systems and apparatus used for cell salvage are described in U.S. Pat. No. 5,976,388, which is incorporated herein by reference.
Another application where separating and processing blood may be desirable is in the removal of unwanted substances from blood or a separated blood component such as plasma. For example, the role of cholesterol and low density lipids (LDL) in cardiovascular disease has been well documented. Methods for lipid removal from the plasma of a patient have been developed and are disclosed in U.S. Pat. Nos. 4,895,558, 5,744,038 and 5,911,698, which are incorporated herein by reference.
Still another application where separating and processing blood may be desirable is in the treatment of blood cells. In a particular application, it may be desirable to treat separated red blood cells with enzymes to, for example, convert Type A, B and AB blood cells to the universally acceptable Type O blood cells. Examples of such methods are described in U.S. Pat. Nos. 6,175,420 and 5,671,135, which are incorporated by reference herein.
As described below, there may be additional applications where it may be desired to separate blood into its components for further treatment and/or processing.
Thus, it would be desirable to provide a single system that, in addition to having the ability of withdrawing whole blood and separating it into two or more components, is programmed for, adaptable for, and capable of carrying out at least two or more applications.
In one aspect, the present invention is directed to an automated system for withdrawing a selected compound from the blood of a patient. The automated system includes a sterile, preassembled, disposable fluid circuit that includes means for withdrawing blood from a patient. The fluid circuit further includes a separation chamber that includes a first sub-chamber for separating a blood component from blood and a second sub-chamber for separating a combination of the blood component and a solvent into a first phase which substantially includes a compound-depleted blood component and a second phase that substantially includes the solvent and the compound.
The fluid circuit further includes a container containing a solvent where the solvent is adapted for extracting a selected compound from the blood component, and means for combining the solvent with the blood. Solvent removal means and means for returning the compound-depleted blood component to the patient are provided.
The fluid circuit further includes a flow control cassette having preformed flow path segments formed therein and separated by valve stations for controlling communication between the segments.
The automated system also includes a re-usable device that includes a means for receiving the chamber and for separating the blood component from the remainder of the blood. The re-usable module also includes means for cooperating with the valve stations to control the flow of the fluid through the preformed flow paths.
In a further, more particular aspect, the fluid circuit may include a first separation means based on a first separation principle for separating (from blood) a blood component including a compound, and a second separation means based on a second separation principle for separating the combination of the blood component and solvent into first and second phases.